The nonconductive substrate for wiring boards and printed circuits must have mechanical strength and chemical resistance in addition to good dielectric properties. Most board materials are thermosetting or thermoplastic resins combined with a reinforcing filler. Typical board construction involves combinations such as phenolic or epoxy resins on paper, paper glass composite, polyimide, polytetrafluoroethylene, etc. In most instances, the board is clad with a thin layer of electroconductive metal such as copper.
Glass/epoxy boards have come to be widely used in the industry when a rigid board is required, rather than a flexible circuit board such as a thermosetting resin without reinforcement filler. The availability of these glass/epoxy boards and their desirable properties contribute to their widespread use in spite of known deficiencies. It has been standard practice to clean out residue in through-holes after drilling the glass/epoxy boards in order to obtain good copper coating in the through-holes. Thus, a substrate with superior properties to glass/epoxy which would not require cleaning after through-hole drilling would represent an advance in the state of the art.
It is an object of the invention to provide a novel nonconducting synthetic fluorhectorite substrate which is suitable for printed copper circuitry and surface mounted electronic components.
It is a further object to provide a method for preparing the fluorhectorite substrate.